Everyday Control Feedback

This is actually a question from a test paper from a engineering course on control theory. --------------------- Identify 10 feedback systems that you encounter in your everyday
environment. For each system, identify the sensing mechanism, actuation mechanism and control computation. Describe the uncertainty with respect to which the feedback system provides robustness and/or the dynamics that are changed through the use of feedback. ---------------------
I can think of a few examples like A toilet water tank, car cruise control, elevator, climate control, heater etc - but I am not sure what's does "control computation" mean in these examples. Also the robustness/dynamics/uncertainty part.
Also, if anyone can think of more everyday examples, it would be great.
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Hi Pp

First, identify the sensing and actuation mechanism for each of your examples. The control computation calculates a change of the actuator depending on what is sensed. This may be a simple mechanical relation in case of the toilet water tank and a complex relation in case of the car cruise control.
I have no idea what they mean by "uncertainty". But if you have written down the control computation it should be possible to say something about dynamics and robustness.

My favorite one is carrying a full coffee mug from the coffee machine to the office desk.
Best regards,
pt
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On 11/16/2011 12:54 AM, Pp wrote:

An obvious one is the body sweating when it is hot to cool it down. Here is a reference
http://en.wikibooks.org/wiki/Human_Physiology/Print_Version
The Human body is full of feedback control mechanism.
"control computation": may be means comparing the output with the desired goal, and then generating a new input to the the actuator in order to bring the output closed to the desired goal?
"robustness/dynamics/uncertainty": may be this is noise part, from outside, which interfere with the actual device being controller, which the controller has no control over. Or noise affecting the sensor itself. I think Robust control is supposed to handle this sort of thing.
--Nasser
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On Wed, 16 Nov 2011 12:24:49 +0530, Pp wrote:

Examples abound if the prof purposely left off "automatic". If not, then after the ones you mentioned there's a host of feedback loops in your own body, regulating blood sugar, CO2 concentrations, temperature, etc. If you can think of it, your body probably has at least one control loop to make it happen.
I _hope_ that he meant 'computation' in the larger sense -- i.e., that an analog circuit with resistors and caps, or some squishy biological system with glands and fluids and other messy stuff counts. If so, then just describe the behavior and mechanism as best as you can (and I very much doubt he's looking for a PhD-level dissertation on each).
As far as the robustness, for example, the body's CO2 system regulates the amount of CO2 by sensing its increase somewhere dark and squishy (the pituitary, I think), and sending hormonal signals to your hindbrain (it's a short trip) that make you want to breath faster. This system also indirectly regulates your oxygen metabolism: more CO2 indirectly indicates less oxygen, so breathing faster oxygenates your blood. This is why medical oxygen has CO2 in it: without CO2 in the oxygen your body's concentration of CO2 gets so low that you stop breathing, your anesthesiologist says "oopsi-daisy", and your undertaker gets some business.
--
Tim Wescott
Control system and signal processing consulting
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On 17-11-2011 03:00 AM, Tim wrote:

Thank you everyone for all the tips. Any more examples from anyone would be great.
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